Shielding lamella

p0001The invention relates to a screen blade for installation as a mass spring ring in a connector having two opposing edge strips which are interconnected by several to transverse and spaced, curved spring strip, said spring strips are curved in their strip plane.

p0002Screen slats are used in connectors, establish a ground connection between the housing of the can and the housing of the connector and shield the cable connection to external electrical interference. For this purpose, it is necessary that the screen blade is able to make a good electrical contact between the socket housing and the plug housing. On the other hand, it is necessary that the earth connection only has a low feedback resistance even after a large number of mating cycles of the connector. During the feedback resistor by applying highly conductive coatings on the can body and the plug housing and on the screen blade at the beginning can be effectively reduced, but often occur after 100 mating cycles by difficulties that the highly conductive surfaces of the shield blades and the connector housing mechanically torn and the airborne pollutants after a few days rest are electrically poor; are formed contamination layers. The relatively low noise voltages that are to be derived on the screen blade, not enough to break through the layers of foreign material.

p0003From DE-OS 3518030 a screen blade of the initially mentioned type is known. As with conventional screen slats also, the individual spring strips are radially outwardly curved, so that they are stressed during mating of the connector to bend. Since the spring strips are curved within the plane of the strip, travels the respective point of contact between a spring strip and the plugged connector housing, thereby forming a very uniform wear of the highly conductive surface layers is to be achieved. Nevertheless, the feedback resistor is also increasing in this screen blade after a few hundred mating cycles Connector sharply.

p0004Object of the present invention is to improve a screen blade of the aforementioned type in such a way that the transfer impedance of a connector remains sufficiently low at the lowest possible surface wear even after several hundred mating cycles.

p0005This object is achieved by the characterizing features of claim 1.

p0006Although is known from DE-AS-2501003 an electrical connector is known which provides between two border strips to transverse, single, double-sided convex curved edges having stripes. These strips are merely twisted around their longitudinal axis, but not arched. The advantage attained with the invention lies in that the individual spring strips are now loaded are not limited to bending or exclusively to torsion, but both bending and torsion. This results in that the spring characteristic of a spring strip is much weaker than in prior art screen slat, as now in each spring strip two springs are connected in series, namely a spiral spring and a torsion spring. This ensures that damage to the highly conductive surfaces of the connector through the screen blade over conventional screen fins is greatly reduced. Despite the softer spring characteristic of each spring strip but a good ground connection between the connector housings is achieved because only takes place a Linienberühung between the spring strips and the adjacent connector housing. This contact takes place on the convex curved edge of a respective spring strip which projects furthest beyond the outer circumference of the screening lamina. Characteristic of this Linienberühung is a high specific pressing force, which is responsible for the low coupling resistance.

p0007According to a preferred embodiment of the invention the intermediate space between two adjacent spring strips is crescent-shaped, so that the convexly curved edge opposite the edge of a spring strip is concavely curved. Thereby, the spring strips narrower, on the one hand decreases its bending rigidity and on the other hand, the effective length of the spring strip is increased.

p0008If the spaces in the center between the edge strips are wider than in the vicinity of the edge strip, which means on the one hand, that the spring strips are narrower than in the border strip at its center, whereby the spring characteristic is even softer, and on the other hand, that interference be better degraded.

p0009To be particularly favorable, it has been found, when the concave curved edge in the middle of the spring strip outside an imaginary, the two connection points of the spring strip is located on the edge strips interconnecting line. Thus, the spring strip extends a considerable distance on the side. This ensures in a simple manner that only the outer, convexly curved edge has contact with the connector housing surrounding the screen blade.

p0010is also particularly advantageous when the edge strips connect tangentially to the spring strip so that intersect the planes of the opposing edge strips. The edge strips are in this manner only with an edge on the inner connector housing; the curvature of the spring strips thus continues in the border strip. This increases the space available for the deflection effective length of the screen blade can be increased, since now take the length of the spring strip and in addition, the widths of the two edge strips of the bending operation during mating of the connector. The spring characteristic of the screen blade is thereby weakened advantageously further.

p0011According to a preferred embodiment, at least one edge strip on its side facing away from the spring strip, in the region of the connecting points of the spring strip recesses. It is thereby achieved that abut the edge of the edge strip only at the positions where no recesses are provided with a uniform pressure on the inner connector housing. This partially same volume resistances are promoted around the screen blade.

p0012It is also advantageous if at least one edge strip on its side facing away from the spring strip spaced from each other and projecting retaining tongues are formed. These retaining tongues can be supported on the inner connector housing, so that the edge strip in question rests in a sliding seat on a receptacle of the connector housing held lying. Thereby, the spring characteristic of the screen blade can further weaken. Advantageously, the screening lamina is punched out of a sheet metal strip.

p0013In the following an embodiment of the invention is explained in more detail with reference to a drawing. Show it:<dl id="dl0001"><dt>Fig. 1</dt><dd>in a schematic perspective view of a erfindungsgemäßte screen blade before its incorporation into a connector,</dd><dt>FIG. 2</dt><dd>the resolution of a screen blade from FIG. 1,</dd><dt>Fig. 3</dt><dd>in a section of a sectional view of an inner housing of a connector with an inserted screen blade,</dd><dt>Fig. 4</dt><dd>in a similar view as in Fig. 3 is an assembled connector, and</dd><dt>Fig. 5</dt><dd>a cross section through a partially illustrated in Fig. 4 connector along the line VV.</dd></dl>

p0014In Fig. 1 a screen blade 1 of the invention is shown for the installation as a mass spring ring into a connector in a perspective view. Fig. 2 shows a developed view in Fig. 1 to a barrel-shaped body bent screen blade 1.

p0015The screen blade 1 comprises two revolving, opposing edge strips 2 and 3, which are interconnected by a plurality of transverse to and spaced apart spring strips. 4 The spring strips 4 are constructed on the one hand, as is apparent from FIGS. 1, 3 and 4, curved, on the other hand they run, such as in particular on Fig. 2 clearly curved in their strip plane. The curvature is so formed that curvature of the outer edge 5 of a spring strip 4 is convexly curved between the terminals 6 and 7 of the spring strip 4 to the opposite edge strips 2 and 3 to one side. The opposite edge 8 of a spring strip 4 is concavely curved. It follows that the spaces 9 assume a crescent shape between two spring strips. 4 In the embodiment shown here, the radius of curvature of the concavely curved edge 8 is chosen to be smaller than that of the convexly curved edge 5. This results in that the spring strips 4 at its center between the two edge strips 2 and 3 are narrower than in the region of the edge strips 2 and 3 and that the spaces 9 in the middle between the edge strips 2 and 3 are wider than in the vicinity of the edge strips 2 and 3. the curvature of the spring strip 4 is so strong that the concavely curved edge 8 in the middle between the edge strips 2 and 3 is located outside an imaginary line 10, 6 and 7, a spring strip 4 connects the connection points to each other.

p0016A marginal strip, here the edge strips 2 of the screen blade 1, has on its side facing away from the spring strips 4 in the field of connection points on 7 recesses 11th The effect of these recesses 11, that the edge of the edge strip 2 is interrupted. On the same edge strip 2 holding tongues 12 are arranged on the side facing away from the spring strip 4 side spaced apart and projecting from the marginal strip second

p0017As particularly well in FIG. 4 can be seen, go to the edge strips 2 and 3 tangentially into the spring strip 4 over, so that the levels 2 and 3 cut E1 and E2 of the edge strip.

p0018The screen blade 1 is punched out in accordance with the blank shown in Fig. 2 from a sheet metal strip. Then, the screen blade 1 provided with a curvature (see. Figs. 3 and 4). Then, the retaining tongues 12 are bent away by approximately 90 °, and the sheet-metal strip bent around so that the screen blade takes the position shown in FIG. 1, barrel-shaped form. In this state, the screen slats are sold as component parts for connectors. In the following, therefore, the function of the screen blade is illustrated in a connector means of the installation.

p0019Fig. 3 shows an inner housing part 13 of a connector with a lateral surface 14 and an adjoining flange 15. The lateral surface 14 is bounded on one side by a stop 16 and the other by the flange 15th In flange part 15 a recess is formed, which is bounded on the outside radially by another attack 17th The screen blade 1 is now so placed on the housing part 13 in that the two edge strips 2 and 3 each rest with its edge on the lateral surface fourteenth The retaining tongues 12 are held in the recess of the flange 15 and allow the edge strips 2 to avoid in the axial direction of the housing part 13 (see FIG. FIG. 4).

p0020Will now be an outer housing part 18 of the plug connector is pushed onto the inner housing part 13, the spring strips 4 are zusammmengedrückt. The contact between the spring strips 4 of the screen blade 1 and the inner cylindrical surface 19 of the housing part 18 is effected substantially exclusively through the convexly curved edge 5 of the spring strips 4 (see. Fig. 5). This is because that the edge tangentially outside the imaginary line 10 lies at a distance a, as shown FIG. 2. This distance a will ensure that the edge 5 is always first 18 comes into contact with the inner cylindrical surface 19 of the housing part. The force acting on the edge 5 loading results firstly in that the spring strips 4, are pressed together as shown in Fig. 4; the spring strips 4 thus subject to a bending stress. Furthermore, the distance A of the rim 5 causes the imaginary connecting line 10, that the spring strip 4 is twisted about the line 10th The spring strips 4 thus acts simultaneously as bending and a torsion spring. From the sectional representation in FIG. 5 can be clearly seen that the individual spring strips 4 abut with their outer, convex curved edge 5 on the inner cylindrical surface 19 of the housing part 18. Further, it can be seen that during mating of the two housing parts 13 and 18 of the contact point between the rim 5 and the inner cylindrical surface 19 does not take place due to the convex curvature of the edge 5 on a axtparallelen line, but that the contact point rather also in the circumferential direction of the cylindrical surface 19 travels.

p0021By the above described formation of the screening lamina is achieved that the spring characteristic thereof is greatly reduced because the spring strip now act both as a bending spring and as a torsion spring, these two springs are connected one behind the other in series. Since the edge strips 2 and 3 lie only with its outer edges on the outer surface 14 of the housing part 13, the time available for a bending of the screen blade effective length is fully exploited. Since no edge strip is firmly clamped, the spring characteristic of the screen blade is further weakened.

p0022Despite this weakening of the spring characteristic curve, which is desirable in order not to damage any surface coatings on the inner cylindrical surface 19 of the housing part 18 even with large mating cycles of the plug connector, the line contact between the edge 5 and the inner cylindrical surface 19 causes a very low transfer impedance between the housing parts 13 and eighteenth